A Canadian-German research team from the Geological Survey has documented a new type of earthquake in Canada. Unlike normal ones, they happen more slowly and last longer.

Hydraulic fracturing during oil and gas production causes tremors. Using a network of eight seismic stations, the researchers recorded data on approximately 350 earthquakes. They were interpreted as intermediate forms of a conventional earthquake and aseismic slip. Aseismic slip occurs near wells.

The researchers explain that earthquakes are caused by hydraulic fracturing. In the process of oil and gas production, a liquid is pumped into the earth, which increases the pressure in the earth’s crust and creates a network of cracks in the subterranean rocks near the wells. If this occurs in rocks where faults already exist, it will cause the fault to slide and cause an earthquake.

Aseismic slip is slow and does not release any seismic energy. Due to the lack of energy, scientists have not yet linked the causes of earthquakes and aseismic vibrations. But they are the ones that cause stress changes in nearby faults. This leads to fast sliding and earthquakes. For the first time, Canadian scientists have discovered a connection between these phenomena.